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From: hpa@casbah.acns.nwu.edu (Peter Anvin)
Newsgroups: comp.lang.c
Subject: Void function pointers
Summary: Can one pass non-void function arguments to functions expecting void?
Keywords: void,function,pointer,ansi,c
Message-ID: <2887@casbah.acns.nwu.edu>
Date: 24 Jan 91 05:28:58 GMT
Distribution: usa
Organization: Northwestern University
Lines: 34

Hello everyone.  Could someone please tell me if this is illegal in ANSI C,
or if only Turbo C++ is picky:

void foo(int p1, double p2, void (*zoom)(int x, double y))
{
    printf("Do something with %d and %ld\n",p1,p2);
    zoom(p1,p2);
}

int bar(int baz, double quux)
{
    printf("Zooming... %lf\n",quux);
    return baz;
}

main()
{
   foo(7,3.141592653938789,bar);         /* Turbo C++ gives hard error here */
   return 0;
}

Turbo C++ always terminates with a hard "Type mismatch" error.  Is this
correct behaviour, and if so, is there a way to declare a pointer to a
function returning *anything or void* but still specify its parameters?

Grateful for answer.
    /Peter

P.S. I haven't been able to figure out... is X3J11 ANSI C *finalized* (ANSI
C-90) or are we still muddling around with working drafts?  
-- 
H. Peter Anvin +++ A Strange Stranger +++ N9ITP/SM4TKN +++
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